Update README.md

README.md

@@ -1,6 +1,8 @@
 # GNOME MPV
 
-GNOME MPV is a simple GTK+ frontend for MPV.
+GNOME MPV is a simple GTK+ frontend for mpv. GNOME MPV interacts with mpv via
+the client API exported by libmpv, allowing access to mpv's powerful playback
+capabilities.
 
 ## Dependencies
 
@@ -18,3 +20,74 @@ GNOME MPV is a simple GTK+ frontend for MPV.
 Run the following command to build and install:
 
     $ autoreconf -sfi && intltoolize -c --automake && ./configure && make && sudo make install
+
+## Usage
+
+### Opening files
+There are 4 ways to open files in GNOME MPV.
+
+1. Passing files and/or URIs as command line arguments.
+2. Using the file chooser dialog box, accessible via the "Open" menu item.
+3. Typing URI into the "Open Location" dialog box, accessible via the
+   menu item with the same name.
+4. Dragging and dropping files or URIs onto GNOME MPV.
+
+### Manipulating playlist
+The playlist is hidden by default. To show the playlist, click the "Playlist"
+menu item or press F9. Files can be added by dragging and dropping files or URIs
+onto the playlist. Dropping files or URIs onto the video area will replace the
+content of the playlist. Playlist files or online playlists (eg. YouTube's
+playlist) will be automatically expanded into individual items when loaded.
+
+Items in the playlist can be reordered via drag-and-drop. To remove items from
+the playlist, select the item by clicking on it then press the delete button on
+your keyboard.
+
+### Configuration
+GNOME MPV can be configured using the preferences dialog box accessible via the
+"Preferences" menu item. Playback-related settings can be loaded from an
+external file using the same syntax as mpv's `mpv.conf`. It is possible to load
+mpv's `mpv.conf` directly with no modification. GNOME MPV will not write to the
+file, so it is not necessary to make a separate copy of the file. The file must
+be specified and enabled in the preferences dialog under the "MPV Configuration"
+section.
+
+Options can also be passed to mpv using the "Extra MPV Options" text box in the
+preferences dialog. The syntax used is the same as mpv's command line options.
+
+### Default keybindings
+Default GUI-related keybindings are defined as following:
+
+|Keys		|Action			|
+|---------------|-----------------------|
+|Ctrl+O		|Open			|
+|Ctrl+L		|Open location		|
+|Ctrl+Q		|Quit			|
+|Ctrl+P		|Preferences		|
+|F9		|Toggle playlist	|
+|F11 or F	|Toggle fullscreen mode	|
+|ESC   		|Exit fullscreen mode	|
+|Ctrl+1		|Normal size		|
+|Ctrl+2		|Double size		|
+|Ctrl+3		|Half size		|
+
+"Normal size", "Double size", and "Half size" resizes GNOME MPV window such that
+the video area is proportional to the size of the playing video. "Normal size"
+will resize the window so that the video area will be the same size as the
+video. "Double size" and "Half size" will resize the window so that the video
+area will be double and half the actual size of the video respectively. Because
+this requires information from the playing video, these actions will have no
+effect if no file is loaded or the current file is an audio file.
+
+There is also another set of default keybindings used for playback-related
+actions. They are defined in the macro `DEFAULT_KEYBINDS`, which can be found
+in [src/def.h](https://github.com/gnome-mpv/gnome-mpv/blob/master/src/def.h).
+The syntax used is exactly the same as mpv's `input.conf`.
+
+Additional keybindings can be defined in an external file using mpv's
+`input.conf` syntax. Because the syntax is the same, it is possible to load
+mpv's `input.conf` directly with no modification. It is not necessary to create
+a separate copy of the file as GNOME MPV will not write to the file. The file
+has to be loaded via the preferences dialog under the "Keybindings" section. In
+case of conflict with default keybindings, keybindings defined in external file
+will be given priority.